{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "3b265051",
   "metadata": {},
   "source": [
    "------\n",
    "* 学习人：林结婷\n",
    "* 时间：2021-11-29\n",
    "* week14\n",
    "* 学习线上资源：[python官方文档](https://www.python.org/)\n",
    "* [老师的博客](https://www.cnblogs.com/xuzhichao/p/11570285.html)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "57cb0766",
   "metadata": {},
   "source": [
    "# 本周学习目标\n",
    "> 1. 函数的定义\n",
    "> 2. 函数的使用\n",
    "> 3. 函数的参数"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "296334ce",
   "metadata": {},
   "source": [
    "## 函数的定义\n",
    "> 1. 定义一个函数的一般步骤"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "22aa7202",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 \n"
     ]
    }
   ],
   "source": [
    "a, b = 0, 1\n",
    "while a < 10:\n",
    "    print(a, end=' ')# 0 1 1\n",
    "    a, b = b, a+b # a = 1 a = 1 b =2 a =2 b = 3\n",
    "print()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "a664706d",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 13 21 34 \n"
     ]
    }
   ],
   "source": [
    "a, b = 0, 1\n",
    "while a < 50:\n",
    "    print(a, end=' ')# 0 1 1\n",
    "    a, b = b, a+b # a = 1 a = 1 b =2 a =2 b = 3\n",
    "print()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "f9c85e04",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 13 21 34 55 89 \n"
     ]
    }
   ],
   "source": [
    "a, b = 0, 1\n",
    "while a < 100:\n",
    "    print(a, end=' ')# 0 1 1\n",
    "    a, b = b, a+b # a = 1 a = 1 b =2 a =2 b = 3\n",
    "print()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "id": "7b546beb",
   "metadata": {},
   "outputs": [],
   "source": [
    "# ........我想重复使用某一个功能（避免重复造轮子）\n",
    "# ........使用的人可以不懂代码，只要会调用函数即可founction_name()\n",
    "def fib(n):    # write Fibonacci series up to n\n",
    "     \"\"\"Print a Fibonacci series up to n.\"\"\"\n",
    "     a, b = 0, 1\n",
    "     while a < n:\n",
    "         print(a, end=' ')\n",
    "         a, b = b, a+b\n",
    "     print()\n"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "419038b5",
   "metadata": {},
   "source": [
    "### 函数的使用"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "id": "222476cf",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 \n"
     ]
    }
   ],
   "source": [
    "fib(10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "id": "665312a4",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 13 21 34 \n"
     ]
    }
   ],
   "source": [
    "fib(50)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "id": "2a6ae451",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 13 21 34 55 89 \n"
     ]
    }
   ],
   "source": [
    "fib(100)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "0e939f89",
   "metadata": {},
   "source": [
    "> 1. 定义函数的一般方法：\n",
    "...\n",
    "def founction_name(): # 1. function_name 遵循变量定义规则 区别数字函数==》 f(x)python的函数可以自定义名称\n",
    "   \"\"\"函数的注释\"\"\"  # 2. 函数的注释可以和使用者交流\n",
    "   函数体        #  3. 函数体要和定义函数保持一定的tab缩进  \n",
    "..."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "id": "05d76bcd",
   "metadata": {},
   "outputs": [],
   "source": [
    "# 1. 请大家写一个函数 实现 hallo world\n",
    "# 2. 请大家写一个函数 实现 hallo username"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "id": "b367811e",
   "metadata": {},
   "outputs": [],
   "source": [
    "def hello():\n",
    "    \"\"\"打印你好，世界\"\"\"\n",
    "    print(\"hello world\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 38,
   "id": "d4bc30cc",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello world\n"
     ]
    }
   ],
   "source": [
    "hello()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "id": "854a2f04",
   "metadata": {},
   "outputs": [],
   "source": [
    "def hello_user(username):\n",
    "    \"\"\"打印，你好，xxx同学~\"\"\"\n",
    "    print(\"你好，\"+ username.title()+\"同学~\")\n",
    "    "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 41,
   "id": "e2f06532",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "你好，Jieting同学~\n"
     ]
    }
   ],
   "source": [
    "hello_user(\"jieting\")"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "b0b99189",
   "metadata": {},
   "source": [
    "* 思考：函数是否必须有参数？\n",
    "* 注意：\n",
    "> 1. （1）在第一行定义函数中，不需要任何信息就能完成工作，因此括号是空的（即便如此，括号必不可少！）\n",
    "\n",
    "> 2. （2）要调用函数，可以依次指定函数名以及括号括起的必要信息。在第五行代码中，因为此函数greet_uesr()括号中不需要任何信息，只需要输入greet_uesr（）即可。和预期效果一样，打印Hello！："
   ]
  },
  {
   "cell_type": "markdown",
   "id": "6708ce5f",
   "metadata": {},
   "source": [
    "## 3.函数的参数\n",
    "> 1. 形式参数：\n",
    ">> 1. 定义函数时，写在function_name里面的参数\n",
    ">> 2. 在定义函数时，形式参数不占用空间\n",
    "> 2. 实际参数：\n",
    ">> 1. 调用函数时，写在function_name括号里面的参数\n",
    ">> 2. 在使用函数时，形式参数被分配空间，变为实际参数"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 43,
   "id": "1162d524",
   "metadata": {},
   "outputs": [],
   "source": [
    "def describe_pet(animal_type,pet_name):# animal_type,pet_name 时是形式参数  形参   \"\"\"显示宠物信息\"\"\"\n",
    "     print(\"\\nI have a\" + animal_type + \".\")\n",
    "     print(\"My\" + animal_type + \"'s name is \"+pet_name.title() + \".\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "id": "5f5bc367",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have adog.\n",
      "Mydog's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(\"dog\",\"豆豆\")# \"dog\",\"豆豆\"实际参数 实参"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 46,
   "id": "9f8881b8",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have a豆豆.\n",
      "My豆豆's name is Dog.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(\"豆豆\",\"dog\")"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "625887d5",
   "metadata": {},
   "source": [
    "* 当函数具有多个参数时\n",
    "> 1. 位置参数\n",
    ">> 1. 形式参数有先后顺序，函数调用过程中应考虑参数的先后顺序，避免出现顺序错误的笑话\n",
    ">> 2. 调用函数过程中要考虑形式参数的个数\n",
    "> 2. 关键字参数\n",
    ">> 1. 调用函数时，通过赋值的方式传递给定义好的形参变量数据\n",
    ">> 2. 关键字参数不考虑先后顺序，因为是指定变量赋值\n",
    "> 3. 默认参数\n",
    ">> 1. 在形式参数中，提前预先设置一个用户可能使用的参数值\n",
    ">> 2. 用户在使用/调用函数时，可以省略不给默认参数值\n",
    ">> 3. 用户给默认参数赋值，将替换默认参数的值"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 47,
   "id": "3dca2251",
   "metadata": {},
   "outputs": [],
   "source": [
    "def describe_pet(animal_type,pet_name):# animal_type,pet_name 时是形式参数  形参   \"\"\"显示宠物信息\"\"\"\n",
    "     print(\"\\nI have a\" + animal_type + \".\")\n",
    "     print(\"My\" + animal_type + \"'s name is \"+pet_name.title() + \".\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 48,
   "id": "20222f07",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have a豆豆.\n",
      "My豆豆's name is Dog.\n"
     ]
    }
   ],
   "source": [
    "# 在使用 describe_pet（）函数时 需要考虑 参数位置，从而进行参数数据的输入（参数的调用）\n",
    "# 位置参数\n",
    "describe_pet(\"豆豆\",\"dog\")# 要根据 形式参数的位置先后 先写animal_type,再写pet_name"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "id": "fb8b136b",
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "describe_pet() missing 2 required positional arguments: 'animal_type' and 'pet_name'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-49-f95e5f55e3d1>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mdescribe_pet\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: describe_pet() missing 2 required positional arguments: 'animal_type' and 'pet_name'"
     ]
    }
   ],
   "source": [
    "describe_pet()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 50,
   "id": "73cd54d0",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have a豆豆.\n",
      "My豆豆's name is Dog.\n"
     ]
    }
   ],
   "source": [
    "# 关键字参数使用\n",
    "describe_pet(animal_type=\"豆豆\",pet_name=\"dog\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "id": "0bb95a1b",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have adog.\n",
      "Mydog's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(pet_name=\"豆豆\",animal_type=\"dog\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 72,
   "id": "007b1965",
   "metadata": {},
   "outputs": [],
   "source": [
    "# 默认参数(写在形式参数中的)\n",
    "def describe_pet(pet_name,animal_type=\"dog\"): # animal_type,pet_name 是形式参数 形参\n",
    "    \"\"\"\n",
    "    显示宠物信息\n",
    "    \n",
    "    通过打印的方式显示宠物类型和宠物名称\n",
    "    参数信息：\n",
    "    pet_name： 是一个字符串，宠物名称\n",
    "    animal_type：是一个字符串，宠物类型\n",
    "    \"\"\"\n",
    "    print(\"\\nI have a \" + animal_type + \".\")\n",
    "    print(\"My \" + animal_type + \"'s name is \"+pet_name.title() + \".\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 73,
   "id": "c0ef8ab2",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have a dog.\n",
      "My dog's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(\"豆豆\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 74,
   "id": "7b94b044",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have a cat.\n",
      "My cat's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(\"豆豆\",\"cat\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 75,
   "id": "0f10a019",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on function describe_pet in module __main__:\n",
      "\n",
      "describe_pet(pet_name, animal_type='dog')\n",
      "    显示宠物信息\n",
      "    \n",
      "    通过打印的方式显示宠物类型和宠物名称\n",
      "    参数信息：\n",
      "    pet_name： 是一个字符串，宠物名称\n",
      "    animal_type：是一个字符串，宠物类型\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(describe_pet)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 58,
   "id": "5cce43fb",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hallo\n",
      "hello\n",
      "hello\n"
     ]
    }
   ],
   "source": [
    "print(\"hallo\",'\\n',\"hello\",sep='')\n",
    "print(\"hello\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "id": "014c4bc1",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on built-in function print in module builtins:\n",
      "\n",
      "print(...)\n",
      "    print(value, ..., sep=' ', end='\\n', file=sys.stdout, flush=False)\n",
      "    \n",
      "    Prints the values to a stream, or to sys.stdout by default.\n",
      "    Optional keyword arguments:\n",
      "    file:  a file-like object (stream); defaults to the current sys.stdout.\n",
      "    sep:   string inserted between values, default a space.\n",
      "    end:   string appended after the last value, default a newline.\n",
      "    flush: whether to forcibly flush the stream.\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(print)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "37915c66",
   "metadata": {},
   "source": [
    "---------\n",
    "参数使用过程中的思考与问题\n",
    "> 1. 思考：关键字参数（调用函数） 和 位置参数（调用函数） 是否可以一起使用？\n",
    ">> 1. positional argument follows keyword argument(位置参数<font style=\"color:red\">均</font>要放在关键字参数前面)\n",
    ">> 2. test1() got multiple values for argument 'x'(映射，不能出现multiple values（多重值） )\n",
    "> 2.定义函数：默认参数（定义函数）和非默认参数（定义函数）的先后关系\n",
    ">> 1. non-default argument follows default argument(非默认参数<font style=\"color:red\">均</font>要放在默认参数前面)\n",
    "---------\n",
    "* 以下为测试代码"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 61,
   "id": "44de5094",
   "metadata": {},
   "outputs": [],
   "source": [
    "# 案例1\n",
    "def test1(x,y,z):\n",
    "    \"\"\"打印x,y,z的值\"\"\"\n",
    "    print(x)\n",
    "    print(y)\n",
    "    print(z)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 62,
   "id": "906795bd",
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "positional argument follows keyword argument (<ipython-input-62-fd583303ea9b>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-62-fd583303ea9b>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    test1(x=2,3,z=4)\u001b[0m\n\u001b[1;37m              ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m positional argument follows keyword argument\n"
     ]
    }
   ],
   "source": [
    "test1(x=2,3,z=4)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 63,
   "id": "305d0814",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "2\n",
      "3\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "test1(2,y=3,z=4)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 64,
   "id": "f0e5d24c",
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "positional argument follows keyword argument (<ipython-input-64-32b91fe9ca8b>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-64-32b91fe9ca8b>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    test1(2,y=3,4)\u001b[0m\n\u001b[1;37m                ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m positional argument follows keyword argument\n"
     ]
    }
   ],
   "source": [
    "test1(2,y=3,4)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 65,
   "id": "51cb1dce",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "2\n",
      "3\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "test1(2,z=4,y=3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 66,
   "id": "16bfeb57",
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "test1() got multiple values for argument 'x'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-66-abf767fdec53>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mtest1\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m2\u001b[0m\u001b[1;33m,\u001b[0m\u001b[0mx\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;36m3\u001b[0m\u001b[1;33m,\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;36m1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: test1() got multiple values for argument 'x'"
     ]
    }
   ],
   "source": [
    "test1(2,x=3,y=1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 67,
   "id": "0829e34f",
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "non-default argument follows default argument (<ipython-input-67-f8826b39bcee>, line 2)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-67-f8826b39bcee>\"\u001b[1;36m, line \u001b[1;32m2\u001b[0m\n\u001b[1;33m    def test1(x,y=3,z):\u001b[0m\n\u001b[1;37m              ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m non-default argument follows default argument\n"
     ]
    }
   ],
   "source": [
    "# 案例2\n",
    "def test1(x,y=3,z):\n",
    "    \"\"\"打印x,y,z的值\"\"\"\n",
    "    print(x)\n",
    "    print(y)\n",
    "    print(z)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 68,
   "id": "de9786ad",
   "metadata": {},
   "outputs": [],
   "source": [
    "def test1(x,z,y=3):\n",
    "    \"\"\"打印x,y,z的值\"\"\"\n",
    "    print(x)\n",
    "    print(y)\n",
    "    print(z)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "8a8e8b6c",
   "metadata": {},
   "source": [
    "## 4.课本练习\n",
    "> 1. 请大家总结函数的优势\n",
    "> 2. 预习课本第四章函数与模块\n",
    ">> 1. 完成课本元音字母实践\n",
    ">> 2.浏览模块，创建模块和调用模块，了解PEP 8 python国际代码标准"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 69,
   "id": "4b259d7c",
   "metadata": {},
   "outputs": [],
   "source": [
    "def search4vowles(word):\n",
    "    \"\"\"判断输入文本出现的元音字母有那些\"\"\"\n",
    "    vowels = set(\"aeiou\")\n",
    "    word = set(word)\n",
    "    print(vowels & word)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 70,
   "id": "4b59ca1a",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'a', 'o'}\n"
     ]
    }
   ],
   "source": [
    "search4vowles(\"jcdkoafddsa\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 71,
   "id": "dddc1601",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'i', 'e', 'a', 'u'}\n"
     ]
    }
   ],
   "source": [
    "search4vowles(\"duaiuaefhda\")"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "f3982274",
   "metadata": {},
   "source": [
    "## 课本练习"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "807ec328",
   "metadata": {},
   "outputs": [],
   "source": [
    "def search4vowels(phrase:str) -> set:\n",
    "    \"\"\"Return any vowels found in a supplied phrase\"\"\"\n",
    "    vowels = set('aeiou')\n",
    "    return vowels.intersection(set(phrase))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "0decbd14",
   "metadata": {},
   "outputs": [],
   "source": [
    "def search4vowels(phrase:str) -> set:\n",
    "    \"\"\"Return any vowels found in a supplied phrase\"\"\"\n",
    "    vowels = set('aeiou')\n",
    "    return vowels.intersection(set(phrase))\n",
    "\n",
    "def search4letters(phrase:str, letters:str) -> set:\n",
    "    return set(letters).intersection(set(phrase))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "919ebea9",
   "metadata": {},
   "outputs": [],
   "source": [
    "def search4vowels(phrase:str) -> set:\n",
    "    \"\"\"Return any vowels found in a supplied phrase\"\"\"\n",
    "    vowels = set('aeiou')\n",
    "    return vowels.intersection(set(phrase))\n",
    "\n",
    "def search4letters(phrase:str, letters:str) -> set:\n",
    "    \"\"\"Return a set of the 'letter' found in 'phrase'\"\"\"\n",
    "    return set(letters).intersection(set(phrase))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "28152950",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on function search4vowels in module __main__:\n",
      "\n",
      "search4vowels(phrase: str) -> set\n",
      "    Return any vowels found in a supplied phrase\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(search4vowels)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "0eda52d0",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on function search4letters in module __main__:\n",
      "\n",
      "search4letters(phrase: str, letters: str) -> set\n",
      "    Return a set of the 'letter' found in 'phrase'\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(search4letters)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "bf84fcfd",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'e', 'i'}"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "search4letters('hitch-hiker','aeiou')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "b5ae4170",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'x', 'y'}"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "search4letters('galaxy','xyz')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "12d57ad2",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "set()"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "search4letters('life,the universe ,and everything','o')"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "0d60fe4a",
   "metadata": {},
   "source": [
    "## 函数的优势\n",
    "* 1.使用 Python 函数来最大程度地减少重复任务编码工作量。(减少重复代码，模块化代码。)\n",
    "* 2.只需嵌入少量可执行代码，就能使代码结构更加简洁，从而大大简化代码复杂性，提高代码可读性。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "bc497a37",
   "metadata": {},
   "outputs": [],
   "source": []
  }
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